scholarly journals Depth of the Steroid Core Location Determines the Mode of Na,K-ATPase Inhibition by Cardiotonic Steroids

2021 ◽  
Vol 22 (24) ◽  
pp. 13268
Author(s):  
Аrtem M. Tverskoi ◽  
Yuri M. Poluektov ◽  
Elizaveta A. Klimanova ◽  
Vladimir A. Mitkevich ◽  
Alexander A. Makarov ◽  
...  
Keyword(s):  
Hydrogen Bond ◽  
Heart Diseases ◽  
Lower Number ◽  
Physiological Effects ◽  
Cytotoxic Effects ◽  
Binding Cavity ◽  
The Difference ◽  
Atpase Inhibition ◽  
Α1 Subunit ◽  
Specific Inhibitors

Cardiotonic steroids (CTSs) are specific inhibitors of Na,K-ATPase (NKA). They induce diverse physiological effects and were investigated as potential drugs in heart diseases, hypertension, neuroinflammation, antiviral and cancer therapy. Here, we compared the inhibition mode and binding of CTSs, such as ouabain, digoxin and marinobufagenin to NKA from pig and rat kidneys, containing CTSs-sensitive (α1S) and -resistant (α1R) α1-subunit, respectively. Marinobufagenin in contrast to ouabain and digoxin interacted with α1S-NKA reversibly, and its binding constant was reduced due to the decrease in the deepening in the CTSs-binding site and a lower number of contacts between the site and the inhibitor. The formation of a hydrogen bond between Arg111 and Asp122 in α1R-NKA induced the reduction in CTSs’ steroid core deepening that led to the reversible inhibition of α1R-NKA by ouabain and digoxin and the absence of marinobufagenin’s effect on α1R-NKA activity. Our results elucidate that the difference in signaling, and cytotoxic effects of CTSs may be due to the distinction in the deepening of CTSs into the binding side that, in turn, is a result of a bent-in inhibitor steroid core (marinobufagenin in α1S-NKA) or the change of the width of CTSs-binding cavity (all CTSs in α1R-NKA).

scholarly journals Ganoderma lucidum (Curt.: Fr.) Karst. – health-promoting properties. A review

2015 ◽  
Vol 61 (3) ◽  
pp. 105-118 ◽  
Author(s):  
Marek Siwulski ◽  
Krzysztof Sobieralski ◽  
Iwona Golak-Siwulska ◽  
Sławomir Sokół ◽  
Agnieszka Sękara
Keyword(s):  
Ganoderma Lucidum ◽  
Heart Diseases ◽  
Physiological Effects ◽  
Fruiting Bodies ◽  
Positive Effects ◽  
Anti Cancer ◽  
Prevention And Treatment ◽  
Life Threatening ◽  
Health Promoting ◽  
Active Substances

SummaryThis paper presents the characteristics of the speciesGanoderma lucidumin terms of health-promoting properties. This species is rare in Poland, and is subject to strict protection. Reishi is classified as a medicinal mushroom which fruiting bodies are characterized by a content of active substances with diverse positive effects on human health.G. lucidumis particularly rich source of bioactive compounds, which are obtained from fruiting bodies, mycelium and spores of this species. The therapeutic effect ofG. lucidumextracts has been demonstrated in many scientific studies. The most important pharmacological and physiological effects include: immunomodulatory, anti-cancer, anti-inflammatory, antiviral, anti-atherosclerosis, antidiabetic and anti-aging. Reishi has also a beneficial effect on liver cells and the cardiovascular system and protects in case of stomach ulcers. Due to its propertiesG. lucidumcan be used in the prevention and treatment of life-threatening diseases, such as cancer, stroke and heart diseases.

Excess volumes of an alcohol + 1,2-dichloroethane

1981 ◽  
Vol 59 (14) ◽  
pp. 2210-2211 ◽  
Author(s):  
Nettem V. Choudary ◽  
Puligundla R. Naidu
Keyword(s):  
Hydrogen Bond ◽  
Hydrogen Bonds ◽  
Binary Mixtures ◽  
Excess Volumes ◽  
Hydrogen Bond Interaction ◽  
Bond Interaction ◽  
Break Up ◽  
The Difference

Excess volumes for binary mixtures of 1,2-dichloroethane with n-propanol, n-butanol, n-pentanol, n-hexanol, n-heptanol, and n-octanol have been determined at 303.15 K. VE is positive over the whole range of composition in all the mixtures. However, it is noticed that the positive values of VE of mixtures of 1,2-dichloroethane with n-hexanol, n-heptanol, and n-octanol differ from those for the mixtures of 1,2-dichloroethane with corresponding alkanes. The difference has been explained in terms of the break up of hydrogen bonds, interstitial accommodation of 1,2-dichloroethane in alcohol aggregates, and possible hydrogen bond interaction of the type Cl … H—O between unlike molecules.

Infrared spectroscopic characterization of hydrogen-bonded propylene oxide − ethanol and propylene oxide − 2-fluoroethanol complexes isolated in solid neon matrices

2013 ◽  
Vol 91 (12) ◽  
pp. 1292-1302 ◽  
Author(s):  
Osama Y. Ali ◽  
Elyse Jewer ◽  
Travis D. Fridgen
Keyword(s):  
Hydrogen Bond ◽  
Propylene Oxide ◽  
Spectroscopic Characterization ◽  
Hydrogen Bond Donor ◽  
Hydrogen Bond Acceptor ◽  
Reduced Frequency ◽  
Enthalpy Of Proton Transfer ◽  
The Difference ◽  
Bonded Complexes ◽  
Hydrogen Bonded

The infrared absorption spectra of hydrogen-bonded complexes of propylene oxide with either ethanol or 2-fluoroethanol have been recorded in neon matrices. Mixtures of propylene oxide and ethanol or propylene oxide and 2-fluoroethanol vapors were mixed with an excess of neon gas and deposited onto a KBr substrate at 4.2 K. The results indicate that hydrogen-bonded complexes were formed with propylene oxide as the hydrogen bond acceptor and either ethanol or 2-fluoroethanol as the hydrogen bond donors. The features assigned to the O−H stretch were red-shifted by 175 and 193 cm−1 for the ethanol- and 2-fluoroethanol-containing complexes, respectively. The difference in red shifts can be accounted for due to the greater acidity of 2-fluroethanol. Deuterium isotope experiments were conducted to help confirm the assignment of the O–H stretch for the complexes. As well, structures and infrared spectra were calculated using B3LYP/6-311++G(2d,2p) calculations and were used to compare with the experimental spectra. A “scaling equation” rather than a scaling factor was used and is shown to greatly increase the utility of the calculations when comparing with experimental spectra. An examination of the O–H stretching red shifts for many hydrogen-bound complexes reveals a relationship between the shift and the difference between the acidity of the hydrogen bond donor and the basicity of the hydrogen bond acceptor (the enthalpy of proton transfer). Both hydrogen-bonded complexes and proton-bound complexes appear to have a maximum in the reduced frequency value that corresponds to complexes where the hydrogen/proton are equally shared between the two bases.

scholarly journals Antibody against viruses in maternal and cord sera: non-specific inhibitors are found to higher titre on the maternal side of the circulation

1984 ◽  
Vol 92 (3) ◽  
pp. 297-301 ◽  
Author(s):  
P. D. Griffiths ◽  
D. Girdhar ◽  
S. Fisher-Hoch ◽  
M. W. Race ◽  
R. B. Heath
Keyword(s):  
Specific Antibody ◽  
Rubella Virus ◽  
Igg Antibodies ◽  
The Difference ◽  
Specific Inhibitors ◽  
Maternal Igg ◽  
Maternal Side

SummaryPregnancies were identified in which maternal IgG antibodies against rubella virus were not detectable by single radial haemolysis. Twenty paired maternal/cord sera were then tested for haemagglutination-inhibiting (HI) activity against rubella virus without kaolin pretreatment of the sera. In the absence of specific antibody, the HI activity observed could thus be ascribed to the effect of non-specific inhibitors. The HI activity in maternal sera was significantly (P < 0·001) higher than that in cord sera. The 20 pairs of sera were similarly tested against a bunyavirus, an alphavirus and a flavivirus, both with and without kaolin pretreatment. The results showed non-specific inhibitors were found to higher titre in maternal sera, with the difference being statistically significant (P < 0·001) for each of the three viruses.

scholarly journals Exploring the Retinal Binding Cavity of Archaerhodopsin-3 by Replacing the Retinal Chromophore With a Dimethyl Phenylated Derivative

2021 ◽  
Vol 8 ◽  
Author(s):  
Taichi Tsuneishi ◽  
Masataka Takahashi ◽  
Masaki Tsujimura ◽  
Keiichi Kojima ◽  
Hiroshi Ishikita ◽  
...  
Keyword(s):  
Energy Gap ◽  
Blue Shift ◽  
Proton Pumping ◽  
Molecular Properties ◽  
Ph Change ◽  
Time Resolved ◽  
Spectroscopic Measurements ◽  
Binding Cavity ◽  
Retinal Chromophore ◽  
The Difference

Rhodopsins act as photoreceptors with their chromophore retinal (vitamin-A aldehyde) and they regulate light-dependent biological functions. Archaerhodopsin-3 (AR3) is an outward proton pump that has been widely utilized as a tool for optogenetics, a method for controlling cellular activity by light. To characterize the retinal binding cavity of AR3, we synthesized a dimethyl phenylated retinal derivative, (2E,4E,6E,8E)-9-(2,6-Dimethylphenyl)-3,7-dimethylnona-2,4,6,8-tetraenal (DMP-retinal). QM/MM calculations suggested that DMP-retinal can be incorporated into the opsin of AR3 (archaeopsin-3, AO3). Thus, we introduced DMP-retinal into AO3 to obtain the non-natural holoprotein (AO3-DMP) and compared some molecular properties with those of AO3 with the natural A1-retinal (AO3-A1) or AR3. Light-induced pH change measurements revealed that AO3-DMP maintained slow outward proton pumping. Noteworthy, AO3-DMP had several significant changes in its molecular properties compared with AO3-A1 as follows; 1) spectroscopic measurements revealed that the absorption maximum was shifted from 556 to 508 nm and QM/MM calculations showed that the blue-shift was due to the significant increase in the HOMO-LUMO energy gap of the chromophore with the contribution of some residues around the chromophore, 2) time-resolved spectroscopic measurements revealed the photocycling rate was significantly decreased, and 3) kinetical spectroscopic measurements revealed the sensitivity of the chromophore binding Schiff base to attack by hydroxylamine was significantly increased. The QM/MM calculations show that a cavity space is present at the aromatic ring moiety in the AO3-DMP structure whereas it is absent at the corresponding β-ionone ring moiety in the AO3-A1 structure. We discuss these alterations of the difference in interaction between the natural A1-retinal and the DMP-retinal with binding cavity residues.

Hydrogen Bonding Contribution to Lipophilicity Parameters. Hydrogen Acceptor and Hydrogen Acceptor Donor Parameters

2004 ◽  
Vol 69 (12) ◽  
pp. 2147-2173 ◽  
Author(s):  
Marvin Charton ◽  
Barbara I. Charton
Keyword(s):  
Hydrogen Bond ◽  
Hydrogen Bonding ◽  
Hydrogen Bonds ◽  
Reasonable Assumption ◽  
Hydrogen Acceptor ◽  
Donor Capacity ◽  
The Difference ◽  
Acceptor Capacity ◽  
Lipophilicity Parameters ◽  
Hydrogen Bond Energies

In our analysis of the composition of lipophilicity parameters by the intermolecular force (IMF) model we have made use of nH, the number of OH and/or NH bonds, as a measure of the hydrogen donor capacity of a substituent; and nn, the number of lone pairs on O and/or N atoms in the substituent, as a measure of the hydrogen acceptor capacity of the substituent. The basis of this method is the reasonable assumption that in 55.6 molar water hydrogen bonding is maximized. The method does not account however for differences in the energy of different types of hydrogen bonds, but further assumes that these differences are to a first approximation negligible. In order to improve the model we have defined a scale of group hydrogen bonding acceptor parameters, ηXHA, and overall hydrogen bond parameters ηXHAD from the water/1-octanol partition coefficients of AkX where Ak is alkyl. These parameters should account for both the extent of hydrogen bonding in water and for the difference in hydrogen bond energies of the various types of hydrogen bonds encountered. Correlations of log P values for Ph(CH2)nX, X1(CH2)X2, and substituted amino acids Xaa with the IMF equation using the ηXHA and ηXHAD parameters demonstrated their use. Correlation of log P values for PhX suggested that for many groups separate sets of ηXHA and ηXHAD values are required when they are bonded to sp2 hybridized carbon rather than sp3 hybridized carbon.

Abstract WP26: Use of Balloon-guide Catheter Bridges the Difference in Technical Outcomes Between Adapt and Stent Retriever Thrombectomy for Ischemic Stroke - Insights From STAR Collaboration

Stroke ◽  
2020 ◽  
Vol 51 (Suppl_1) ◽  
Author(s):  
Ali M Alawieh ◽  
Reda Chalhoub ◽  
Mohammad Anadani ◽  
Maya Eid ◽  
Eyad Almallouhi ◽  
...  
Keyword(s):  
Ischemic Stroke ◽  
Independent Predictor ◽  
Star Collaboration ◽  
Lower Number ◽  
Stent Retriever ◽  
Procedure Time ◽  
Aspiration Thrombectomy ◽  
Guide Catheter ◽  
Significant Difference ◽  
The Difference

Introduction: Recently completed randomized controlled trials comparing aspiration thrombectomy (ADAPT) to stent retriever thrombectomy (SRT) demonstrated similar clinical outcomes, but faster thrombectomy procedure time in the ADAPT group. This study evaluates the difference in technical outcomes between ADAPT and SRT combined with balloon-guide catheters (BGC). Methods: Patients undergoing thrombectomy for acute ischemic stroke at 12 comprehensive stroke centers in the US and Europe between 01/2013 and 12/2018 were reviewed. Data was collected retrospectively from patient charts, procedure notes, and patient follow-up in neurology clinics. Clinical endpoint was the modified Rankin score (mRS) at 90-days, and technical outcomes were procedure time, total attempts, and mTICI scores. Results: The study included 2,016 patients (mean age 69±15) who underwent stroke thrombectomy using ADAPT (46%), SRT (46%), or SRT+BGC (8%). Similar baseline characteristics were observed between the three groups, and no significant difference in mRS scores at 90-days between the three groups in univariate and multivariate analyses. Thrombectomy performed using SRT+BGC required significantly shorter procedure time compared to SRT (35 vs 61 min, p<0.001) that was comparable to ADAPT (36 min, p>0.1). However, use of SRT+BGC required significantly lower number of aspiration attempts compared to ADAPT (median 1 vs. 2, p<0.05). On multivariate linear regression, use of SRT+BGC independent predicted a significant reduction in procedure time compared to SRT (coefficient=-30.6, p<0.001), and significantly lower number of attempts compared to ADAPT (coefficient=-0.4, p=0.01). SRT+BGC was an independent predictor of higher mortality compared to ADAPT (OR=2.4, p<0.01), despite comparable rates of favorable outcomes (mRS 0-2) between the two groups. Use of SRT+BGC was not an independent predictor of symptomatic hemorrhage or complications compared to SRT or ADAPT. Conclusions: This study shows that although ADAPT allows for faster procedure time compared to SRT, the use of BGC in SRT allows for a comparable procedure time to ADAPT with similar overall rates of favorable outcome, complications and hemorrhage. Mortality was higher with the use of BGC compared to ADAPT.

Denervation enhances the physiological effects of the KATP channel during fatigue in EDL and soleus muscle

2001 ◽  
Vol 281 (1) ◽  
pp. R56-R65 ◽  
Author(s):  
W. Matar ◽  
J. A. Lunde ◽  
B. J. Jasmin ◽  
J.-M. Renaud
Keyword(s):  
Soleus Muscle ◽  
Katp Channel ◽  
Extensor Digitorum Longus ◽  
Channel Blocker ◽  
Major Effect ◽  
Physiological Effects ◽  
Denervated Muscle ◽  
Resting Tension ◽  
The Difference ◽  
Denervated Muscles

The objective was to determine whether denervation reduces or enhances the physiological effects of the KATP channel during fatigue in mouse extensor digitorum longus (EDL) and soleus muscle. For this, we measured the effects of 100 μM of pinacidil, a channel opener, and of 10 μM of glibenclamide, a channel blocker, in denervated muscles and compared the data to those observed in innervated muscles from the study of Matar et al. (Matar W, Nosek TM, Wong D, and Renaud JM. Pinacidil suppresses contractility and preserves energy but glibenclamide has no effect during fatigue in skeletal muscle. Am J Physiol Cell Physiol 278: C404–C416, 2000). Pinacidil increased the 86Rb+ fractional loss during fatigue, and this effect was 2.6- to 3.4-fold greater in denervated than innervated muscle. Pinacidil also increased the rate of fatigue; for EDL the effect was 2.5-fold greater in denervated than innervated muscle, whereas for soleus the difference was 8.6-fold. A major effect of glibenclamide was an increase in resting tension during fatigue, which was for the EDL and soleus muscle 2.7- and 1.9-fold greater, respectively, in denervated than innervated muscle. A second major effect of glibenclamide was a reduced capacity to recover force after fatigue, an effect observed only in denervated muscle. We therefore suggest that the physiological effects of the KATP channel are enhanced after denervation.

scholarly journals Synthesis and crystal structure of methyl 3-(3-hydroxy-3-phenylprop-2-enoyl)benzoate

2018 ◽  
Vol 74 (6) ◽  
pp. 816-819
Author(s):  
Irina S. Zharinova ◽  
Alfiya A. Bilyalova ◽  
Stanislav I. Bezzubov
Keyword(s):  
Hydrogen Bond ◽  
Tautomeric Form ◽  
Crystal Packing ◽  
Analytical Techniques ◽  
X Ray Diffraction ◽  
Synthesis And Crystal Structure ◽  
Compound C ◽  
Vis Spectroscopy ◽  
Density Map ◽  
The Difference

The title compound, C17H14O4, was synthesized under mild conditions and characterized by various analytical techniques. Combined NMR and X-ray diffraction data show that the substance exists exclusively in the enol tautomeric form. An intramolecular ...O=C—C=C—OH... hydrogen bond is present in the molecular structure. The analysis of the difference density map disclosed two adjacent positions of a disordered hydrogen atom taking part in this hydrogen bond, indicating the presence of two enol tautomers in the crystal. The enol molecules are assembled through numerous C—H...π and π–π as well as weak C(aryl)—H...O interactions, thus forming a dense crystal packing. The obtained substance was also studied by UV–Vis spectroscopy and cyclic voltammetry.

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